The end result:
the two vertical needles indicate the part I frogged and rebuilt. Everything between those needles has been frogged, down to the acorn marker that marks the centre of the steek.
This is where I started:
The steek is positioned 10 stitched too much on the right. And I forgot to do the decreases in the first couple of rows above the marker.
Here’s everything frogged and the marker positioned at the stitch that has to be the new middle of the steek. Steek will be 8 st wide total, 4 st to each side of the marker. Decreases will be 2 stitches away from the steek.
Having determined what goes where I now have to sort out which yarn goes in which row and in what colour sequence. That spaghetti is daunting…
Figuring out which two colours belonged to which row was best done from the Wrong Side of the work. For the first six rows I parked them and marked them. The red pin on the bottom left holds the two yarn for the first row. One yarn I found at the edge of the frogged work, the other I found by “walking” along that row until I found a dangling colour:
I then took the first two colours, tried to read the colour pattern of the existing row, and knitted the live stitches in that pattern, except the stitch with the marker on on top of which I cast on 8 stitches.
Having knit from right to left I met the existing knitting on the left and found out I had knitted way and way tighter than the existing gauge. There was still length of yarns left but no more stitches needed:
I don’t know what went wrong. Gauge for sure, I’m nervous doing this and yanking the yarn. I also do not remember whit what colours I casted on those extra 8 stitches the first time around. I probably used more green then yellow then, seeing as I now have more green than yellow left.
I undid the row and knitted it again, trying to have a looser gauge and trying to use equal amounts of colour for the 8 cast on stitches. It didn’t work. I tried again. I tried loosening every stitch after I knit the whole row, to make the yarn more equally distributed. Didn’t work.
Then I gave up. Then I decided to knit the right half of the row from the right side and the left half from the left side. The extra yarn would end up in the middle (of the steek) and that would be alright because eventually this is where the steek will be cut so these extra ends won’t matter. I am at peace with my gauge for now being tighter than the rest of the vest. It’s only a detail.
Here’s how that first row looks after this approach (not all steek stitches have been cast on yet):
That’s ok. That’ll do.
So that’s how I worked it. Pick the two yarns appropriate for the row. Figure out the stitch pattern for that row. Work one half from the left. Work the other half from the right. Remember to do a decrease every third row. Leave extra length in the middle of the steek and be cool with that.
Here I am half way. Not trying to panic over looks and the yarn spaghetti:
Still so much yarn spaghetti!
Don’t panic. Just keep working, one row at the time.
Eventually I reached the top. The spaghetti sorted itself out, two strands at a time. The middle looks weird and messy but it is correct technically. If I pull on the loose parts the neighbouring stitches will tighten and it will look better.
The sides of the steek look good too. Patterns continue. There are decreases. I think I’m alright.
It took 5 hours, over the course of a couple of days.